KDE 4.6 is really, really nice. It's a lot faster than 4.4 on equivalent hardware, they have a native Gtk Oxygen theme that finally makes all your applications look the same, and Activities is finally starting to make some sense. I've used GNOME and KDE both since *buntu 8.04, and KDE 4.6 is better than GNOME 2 will ever be at this point. I haven't tried GNOME 3 yet, and I don't know if I ever will, but that doesn't mean it's universally crap.